Pronunciation: (fi-del'i-tE, fI-), [key]ân.,âpl.-ties.1. strict observance of promises, duties, etc.: a servant's fidelity.2. loyalty: fidelity to one's country.3. conjugal faithfulness.4. adherence to fact or detail.5. accuracy; exactness: The speech was transcribed with great fidelity.6. Audio.,Video.the degree of accuracy with which sound or images are recorded or reproduced.